fix setting UI config to empty for AI custom & displayed models

[Light2Dark]

📝 Summary

There is a bug where untoggling providers/models would not save the config. It's because RHF does not consider them dirty (they have returned to default values). This adds some manual tracking for certain fields & injecting the config.

The other solution I explored was changing the API to be list[str] | "all" maybe, so default value is not empty list. But I am hesitant to make an API change.

🔍 Description of Changes

📋 Checklist

• I have read the contributor guidelines.
• For large changes, or changes that affect the public API: this change was discussed or approved through an issue, on Discord, or the community discussions (Please provide a link if applicable).
• Tests have been added for the changes made.
• Documentation has been updated where applicable, including docstrings for API changes.
• Pull request title is a good summary of the changes - it will be used in the release notes.

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Review	Updated (UTC)
marimo-docs	Ready	Preview, Comment	Jan 27, 2026 5:17am